Collimating and beam expanding laser system can be used in laser distance, laser cutting, space optics, laser interferometer and other fields. The main function of this system is aimed to reach the reqiurements of the system apreture though reducing the spatial divergence angles of the laser beam and then improving the beam collimation. Based on the priniple of non-focus zoom and with the help of analog of Zemax software, a collimating and beam expanding system is introduced: the wavelength of incident laser is 1064 nm; the value of divergence angle is less than 5 mrad; the diameter of incidence is 1 mm; the ratio of beam expanding is continually 4~24, which can help to reduce the beam divergence angle (the minimum angle is 0.208 mrad) and expand the spot size. With different ratios of the system, the root mean square (RMS) value of maximum wave aberration is 0.1769 λ (less than λ/4), which meets the requrements for image quality evaluation. The advantages of this system are simple, easily installed and ajusted, and also widely used in different projects.